Method of making an improved slot drainage culvert

ABSTRACT

An open slot culvert for positioning in a drainage area with the open slot at the top so that any surface drainage water will flow through the slot and directly into the culvert, including a method and apparatus for its manufacture. The improved open slot culvert comprises a metallic, pipe section, split longitudinally along its upper side to form a narrow slot, and grate means, including two spaced, vertical bearing members joined by spacer means, secured in the slot. The method of making the improved open slot culvert includes the steps of providing two elongated, parallel, vertical members in spaced relation having a plurality of spacer means therebetween, longitudinally splitting the upper side of a metallic pipe section to form a narrow slot, and properly positioning the grate means within the narrow slot. The apparatus for making the improved open slot culvert generally comprises an entry pipe station, a pipe clamp, saw and tack welding station, and a finish welding and exit station.



1. A method of making an open slot culvert, for positioning in drainage area with the open slot at the top so that any surface drainage water will flow through the slot and directly into the culvert, the culvert being satisfactorily backfilled by utilizing any suitable material with the upper surface of the drainage area being substantially on a level with the upper surface of the open slot of the culvert, of the type which includes a metallic pipe section, split longitudinally along its upper side to form a narrow slot, and grate means secured in said slot, said grate means comprising two spaced, vertical bearing members substantially normal to the axis of said pipe section and extending longitudinally over the major portion of the length of said slot and being joined by spacer means substantially normal to said vertical bearing members and being located substantially at the neutral axis of the pipe section wall, which comprises the steps: a. providing a grate means comprising two elongated parallel vertical bearing members in spaced relation and joined by spacer means substantially normal to said bearing members; b. longitudinally splitting a metallic pipe section along its upper end to form a narrow slot; c. inserting said grate means within said slot; d. setting the position of said bearing members so that they are substantially normal to the axis of said pipe section and so that said spacer means are located substantially at the neutral axis of the pipe section wall; and e. welding both sides of said grate means to said pipe section wall.
 2. The method according to claim 1, wherein said pipe section is corrugated and including the steps of welding said grate means to said pipe section wall by fillet welding said bearing members at selected crests and valleys of the corrugations of said pipe section wall, and coating the fillet welds with a protective coating.
 3. The method according to claim 2, including the step of bowing the central portion of said pipe section upwardly before welding said bearing members thereto, whereby compensation is provided for a reverse type of bowing, which occurs after fabrication, and a straight culvert is made with substantially no residual stresses remaining in said pipe section after welding to subsequently cause distortion therein at a later time.
 4. The method according to claim 2, wherein said protective coating is zinc.
 5. The method according to claim 2, wherein said protective coating is a zinc dust primer.
 6. The method according to claim 2, wherein said protective coating is an asphalt paint.
 7. The method according to claim 2, wherein only every other one of the corrugation top fillet welds is made during a first fillet welding operation, and wherein said pipe is moved to a final weld position at which the balance of the fillet welds, including the corrugation valley fillet welds are made. 